Living in the environment regulation and control

Neuroscience for kids a good reference site

External Environment

Cell or Multicellular Organism

Internal Environment

bull The outside world that organisms survive and live

in bull Environmental conditions

bull For efficient and sustainable life the inputs of cells organisms must have balanced inputs and outputs

INPUTS OUTPUTS Processes

bull Generally

ndash as temperature increases chemical reactions speed up

ndash as temperature decreases chemical reactions slow down

bull In extremely low temperatures life is not possible because the chemical reactions required occur too slowly

bull At higher temperatures the compounds cells are made of start to breakdown ( eg proteins denature) and again the chemical reactions required for life cease to occur

bull Life therefore has upper and lower limits with respect to environmental temperature

bull This is also the case for other environmental factors such as salinity water pH light etc etc

bull The range over which life is possible is called the lsquoRange of Tolerancersquo

Environmental Gradient

Comp

Level

Met

ab

oli

sm

(eg

g

row

th re

pro

du

ctio

n)

Range of Tolerance

Zone of

stress

Zone of

stress

Death Death

bull All organisms have tolerance limits within which they can function

bull Multi-cellular organisms are part of a larger organisation they are able to have an extra barrier against the external environment

bull This creates an internal environment that can be (to some extent) controlled or adjusted to change

bull This enables the internal cell environments to be relatively constant despite variations in the external environment

Processes Heat

Generation

Heat Input Heat Output

A failure to balance heat input and heat output

Homeostasis the maintenance of relatively stable conditions in the

internal environment of the body despite variations in the external environment

Factors such as

ndash blood pressure ndash body temperature ndash respiration rate ndash blood glucose levels ndash pH ndash Ions ndash O2 and CO2 levels ndash Nutritional needs ndash H2O levels

bull are maintained within a range of normal values around a set point despite constantly changing external conditions

bull Homeostasis requires the body being able to

ndash detect external changes

ndash Implement internal changes to compensate

The Stimulus - Response Model

The Stimulus - Response Model

Heat

Cools

The Stimulus Response Model

How can the body control the response 1 Disrupt the signal transduction pathway

2 Removal of the original stimulus 3 Responding in a way that alters the original signal Feedback

2

1

Negative feedback mechanisms result in control

Negative Feedback result in control

Negative Feedback Mechanism

Positive feedback results in stimulating an effect

bull Works by adding to the stimulus and increasing the effect of it

Positive feedback

Positive feedback

Mechanisms enabling Homeostasis

Negative feedback model

Modes of Transmission Hormonal system bull Slow ( 30-178cmsec)

bull Involves chemical messengers

bull Act by binding to specific receptors on target cells after travelling through the blood stream

bull Can be more long term effect

Nervous system bull Fast ( 1-120msec)

bull Act by sending electrical impulses along neuron cells

bull Short term effect

The nervous system is a rapid response to stimuli It is a more direct communication pathway than hormones

Nerve Structure

The nervous system is made up of neuron cells that send an electrical impulse along from one neuron to the next

The nerve impulse is essentially an electro

chemical impulse resulting from the rapid movement

of ions across the membrane of the neurons

The Nerve impulse

Nerve impulse s are an electrical signal that travels along an axon There is an electrical difference between the inside of the axon and its surroundings When the nerve is activated there is a sudden change in the voltage across the wall of the axon caused by the movement of ions in and out of the neuron This triggers a wave of electrical activity that passes from the cell body along the length of the axon to the synapse

bull For efficient and sustainable life the inputs of cells organisms must have balanced inputs and outputs

INPUTS OUTPUTS Processes

bull Generally

ndash as temperature increases chemical reactions speed up

ndash as temperature decreases chemical reactions slow down

bull In extremely low temperatures life is not possible because the chemical reactions required occur too slowly

bull At higher temperatures the compounds cells are made of start to breakdown ( eg proteins denature) and again the chemical reactions required for life cease to occur

bull Life therefore has upper and lower limits with respect to environmental temperature

bull This is also the case for other environmental factors such as salinity water pH light etc etc

bull The range over which life is possible is called the lsquoRange of Tolerancersquo

Environmental Gradient

Comp

Level

Met

ab

oli

sm

(eg

g

row

th re

pro

du

ctio

n)

Range of Tolerance

Zone of

stress

Zone of

stress

Death Death

bull All organisms have tolerance limits within which they can function

bull Multi-cellular organisms are part of a larger organisation they are able to have an extra barrier against the external environment

bull This creates an internal environment that can be (to some extent) controlled or adjusted to change

bull This enables the internal cell environments to be relatively constant despite variations in the external environment

Processes Heat

Generation

Heat Input Heat Output

A failure to balance heat input and heat output

Homeostasis the maintenance of relatively stable conditions in the

internal environment of the body despite variations in the external environment

Factors such as

ndash blood pressure ndash body temperature ndash respiration rate ndash blood glucose levels ndash pH ndash Ions ndash O2 and CO2 levels ndash Nutritional needs ndash H2O levels

bull are maintained within a range of normal values around a set point despite constantly changing external conditions

bull Homeostasis requires the body being able to

ndash detect external changes

ndash Implement internal changes to compensate

The Stimulus - Response Model

The Stimulus - Response Model

Heat

Cools

The Stimulus Response Model

How can the body control the response 1 Disrupt the signal transduction pathway

2 Removal of the original stimulus 3 Responding in a way that alters the original signal Feedback

2

1

Negative feedback mechanisms result in control

Negative Feedback result in control

Negative Feedback Mechanism

Positive feedback results in stimulating an effect

bull Works by adding to the stimulus and increasing the effect of it

Positive feedback

Positive feedback

Mechanisms enabling Homeostasis

Negative feedback model

Modes of Transmission Hormonal system bull Slow ( 30-178cmsec)

bull Involves chemical messengers

bull Act by binding to specific receptors on target cells after travelling through the blood stream

bull Can be more long term effect

Nervous system bull Fast ( 1-120msec)

bull Act by sending electrical impulses along neuron cells

bull Short term effect

The nervous system is a rapid response to stimuli It is a more direct communication pathway than hormones

Nerve Structure

The nervous system is made up of neuron cells that send an electrical impulse along from one neuron to the next

The nerve impulse is essentially an electro

chemical impulse resulting from the rapid movement

of ions across the membrane of the neurons

The Nerve impulse

Nerve impulse s are an electrical signal that travels along an axon There is an electrical difference between the inside of the axon and its surroundings When the nerve is activated there is a sudden change in the voltage across the wall of the axon caused by the movement of ions in and out of the neuron This triggers a wave of electrical activity that passes from the cell body along the length of the axon to the synapse

bull Generally

ndash as temperature increases chemical reactions speed up

ndash as temperature decreases chemical reactions slow down

bull In extremely low temperatures life is not possible because the chemical reactions required occur too slowly

bull At higher temperatures the compounds cells are made of start to breakdown ( eg proteins denature) and again the chemical reactions required for life cease to occur

bull Life therefore has upper and lower limits with respect to environmental temperature

bull This is also the case for other environmental factors such as salinity water pH light etc etc

bull The range over which life is possible is called the lsquoRange of Tolerancersquo

Environmental Gradient

Comp

Level

Met

ab

oli

sm

(eg

g

row

th re

pro

du

ctio

n)

Range of Tolerance

Zone of

stress

Zone of

stress

Death Death

bull All organisms have tolerance limits within which they can function

bull Multi-cellular organisms are part of a larger organisation they are able to have an extra barrier against the external environment

bull This creates an internal environment that can be (to some extent) controlled or adjusted to change

bull This enables the internal cell environments to be relatively constant despite variations in the external environment

Processes Heat

Generation

Heat Input Heat Output

A failure to balance heat input and heat output

Homeostasis the maintenance of relatively stable conditions in the

internal environment of the body despite variations in the external environment

Factors such as

ndash blood pressure ndash body temperature ndash respiration rate ndash blood glucose levels ndash pH ndash Ions ndash O2 and CO2 levels ndash Nutritional needs ndash H2O levels

bull are maintained within a range of normal values around a set point despite constantly changing external conditions

bull Homeostasis requires the body being able to

ndash detect external changes

ndash Implement internal changes to compensate

The Stimulus - Response Model

The Stimulus - Response Model

Heat

Cools

The Stimulus Response Model

How can the body control the response 1 Disrupt the signal transduction pathway

2 Removal of the original stimulus 3 Responding in a way that alters the original signal Feedback

2

1

Negative feedback mechanisms result in control

Negative Feedback result in control

Negative Feedback Mechanism

Positive feedback results in stimulating an effect

bull Works by adding to the stimulus and increasing the effect of it

Positive feedback

Positive feedback

Mechanisms enabling Homeostasis

Negative feedback model

Modes of Transmission Hormonal system bull Slow ( 30-178cmsec)

bull Involves chemical messengers

bull Act by binding to specific receptors on target cells after travelling through the blood stream

bull Can be more long term effect

Nervous system bull Fast ( 1-120msec)

bull Act by sending electrical impulses along neuron cells

bull Short term effect

The nervous system is a rapid response to stimuli It is a more direct communication pathway than hormones

Nerve Structure

The nervous system is made up of neuron cells that send an electrical impulse along from one neuron to the next

The nerve impulse is essentially an electro

chemical impulse resulting from the rapid movement

of ions across the membrane of the neurons

The Nerve impulse

Nerve impulse s are an electrical signal that travels along an axon There is an electrical difference between the inside of the axon and its surroundings When the nerve is activated there is a sudden change in the voltage across the wall of the axon caused by the movement of ions in and out of the neuron This triggers a wave of electrical activity that passes from the cell body along the length of the axon to the synapse

bull Life therefore has upper and lower limits with respect to environmental temperature

bull This is also the case for other environmental factors such as salinity water pH light etc etc

bull The range over which life is possible is called the lsquoRange of Tolerancersquo

Environmental Gradient

Comp

Level

Met

ab

oli

sm

(eg

g

row

th re

pro

du

ctio

n)

Range of Tolerance

Zone of

stress

Zone of

stress

Death Death

bull All organisms have tolerance limits within which they can function

bull Multi-cellular organisms are part of a larger organisation they are able to have an extra barrier against the external environment

bull This creates an internal environment that can be (to some extent) controlled or adjusted to change

bull This enables the internal cell environments to be relatively constant despite variations in the external environment

Processes Heat

Generation

Heat Input Heat Output

A failure to balance heat input and heat output

Homeostasis the maintenance of relatively stable conditions in the

internal environment of the body despite variations in the external environment

Factors such as

ndash blood pressure ndash body temperature ndash respiration rate ndash blood glucose levels ndash pH ndash Ions ndash O2 and CO2 levels ndash Nutritional needs ndash H2O levels

bull are maintained within a range of normal values around a set point despite constantly changing external conditions

bull Homeostasis requires the body being able to

ndash detect external changes

ndash Implement internal changes to compensate

The Stimulus - Response Model

The Stimulus - Response Model

Heat

Cools

The Stimulus Response Model

How can the body control the response 1 Disrupt the signal transduction pathway

2 Removal of the original stimulus 3 Responding in a way that alters the original signal Feedback

2

1

Negative feedback mechanisms result in control

Negative Feedback result in control

Negative Feedback Mechanism

Positive feedback results in stimulating an effect

bull Works by adding to the stimulus and increasing the effect of it

Positive feedback

Positive feedback

Mechanisms enabling Homeostasis

Negative feedback model

Modes of Transmission Hormonal system bull Slow ( 30-178cmsec)

bull Involves chemical messengers

bull Act by binding to specific receptors on target cells after travelling through the blood stream

bull Can be more long term effect

Nervous system bull Fast ( 1-120msec)

bull Act by sending electrical impulses along neuron cells

bull Short term effect

The nervous system is a rapid response to stimuli It is a more direct communication pathway than hormones

Nerve Structure

The nervous system is made up of neuron cells that send an electrical impulse along from one neuron to the next

The nerve impulse is essentially an electro

chemical impulse resulting from the rapid movement

of ions across the membrane of the neurons

The Nerve impulse

Nerve impulse s are an electrical signal that travels along an axon There is an electrical difference between the inside of the axon and its surroundings When the nerve is activated there is a sudden change in the voltage across the wall of the axon caused by the movement of ions in and out of the neuron This triggers a wave of electrical activity that passes from the cell body along the length of the axon to the synapse

Environmental Gradient

Comp

Level

Met

ab

oli

sm

(eg

g

row

th re

pro

du

ctio

n)

Range of Tolerance

Zone of

stress

Zone of

stress

Death Death

bull All organisms have tolerance limits within which they can function

bull Multi-cellular organisms are part of a larger organisation they are able to have an extra barrier against the external environment

bull This creates an internal environment that can be (to some extent) controlled or adjusted to change

bull This enables the internal cell environments to be relatively constant despite variations in the external environment

Processes Heat

Generation

Heat Input Heat Output

A failure to balance heat input and heat output

Homeostasis the maintenance of relatively stable conditions in the

internal environment of the body despite variations in the external environment

Factors such as

ndash blood pressure ndash body temperature ndash respiration rate ndash blood glucose levels ndash pH ndash Ions ndash O2 and CO2 levels ndash Nutritional needs ndash H2O levels

bull are maintained within a range of normal values around a set point despite constantly changing external conditions

bull Homeostasis requires the body being able to

ndash detect external changes

ndash Implement internal changes to compensate

The Stimulus - Response Model

The Stimulus - Response Model

Heat

Cools

The Stimulus Response Model

How can the body control the response 1 Disrupt the signal transduction pathway

2 Removal of the original stimulus 3 Responding in a way that alters the original signal Feedback

2

1

Negative feedback mechanisms result in control

Negative Feedback result in control

Negative Feedback Mechanism

Positive feedback results in stimulating an effect

bull Works by adding to the stimulus and increasing the effect of it

Positive feedback

Positive feedback

Mechanisms enabling Homeostasis

Negative feedback model

Modes of Transmission Hormonal system bull Slow ( 30-178cmsec)

bull Involves chemical messengers

bull Act by binding to specific receptors on target cells after travelling through the blood stream

bull Can be more long term effect

Nervous system bull Fast ( 1-120msec)

bull Act by sending electrical impulses along neuron cells

bull Short term effect

The nervous system is a rapid response to stimuli It is a more direct communication pathway than hormones

Nerve Structure

The nervous system is made up of neuron cells that send an electrical impulse along from one neuron to the next

The nerve impulse is essentially an electro

chemical impulse resulting from the rapid movement

of ions across the membrane of the neurons

The Nerve impulse

Nerve impulse s are an electrical signal that travels along an axon There is an electrical difference between the inside of the axon and its surroundings When the nerve is activated there is a sudden change in the voltage across the wall of the axon caused by the movement of ions in and out of the neuron This triggers a wave of electrical activity that passes from the cell body along the length of the axon to the synapse

bull All organisms have tolerance limits within which they can function

bull Multi-cellular organisms are part of a larger organisation they are able to have an extra barrier against the external environment

bull This creates an internal environment that can be (to some extent) controlled or adjusted to change

bull This enables the internal cell environments to be relatively constant despite variations in the external environment

Processes Heat

Generation

Heat Input Heat Output

A failure to balance heat input and heat output

Homeostasis the maintenance of relatively stable conditions in the

internal environment of the body despite variations in the external environment

Factors such as

ndash blood pressure ndash body temperature ndash respiration rate ndash blood glucose levels ndash pH ndash Ions ndash O2 and CO2 levels ndash Nutritional needs ndash H2O levels

bull are maintained within a range of normal values around a set point despite constantly changing external conditions

bull Homeostasis requires the body being able to

ndash detect external changes

ndash Implement internal changes to compensate

The Stimulus - Response Model

The Stimulus - Response Model

Heat

Cools

The Stimulus Response Model

How can the body control the response 1 Disrupt the signal transduction pathway

2 Removal of the original stimulus 3 Responding in a way that alters the original signal Feedback

2

1

Negative feedback mechanisms result in control

Negative Feedback result in control

Negative Feedback Mechanism

Positive feedback results in stimulating an effect

bull Works by adding to the stimulus and increasing the effect of it

Positive feedback

Positive feedback

Mechanisms enabling Homeostasis

Negative feedback model

Modes of Transmission Hormonal system bull Slow ( 30-178cmsec)

bull Involves chemical messengers

bull Act by binding to specific receptors on target cells after travelling through the blood stream

bull Can be more long term effect

Nervous system bull Fast ( 1-120msec)

bull Act by sending electrical impulses along neuron cells

bull Short term effect

The nervous system is a rapid response to stimuli It is a more direct communication pathway than hormones

Nerve Structure

The nervous system is made up of neuron cells that send an electrical impulse along from one neuron to the next

The nerve impulse is essentially an electro

chemical impulse resulting from the rapid movement

of ions across the membrane of the neurons

The Nerve impulse

Nerve impulse s are an electrical signal that travels along an axon There is an electrical difference between the inside of the axon and its surroundings When the nerve is activated there is a sudden change in the voltage across the wall of the axon caused by the movement of ions in and out of the neuron This triggers a wave of electrical activity that passes from the cell body along the length of the axon to the synapse

bull Multi-cellular organisms are part of a larger organisation they are able to have an extra barrier against the external environment

bull This creates an internal environment that can be (to some extent) controlled or adjusted to change

bull This enables the internal cell environments to be relatively constant despite variations in the external environment

Processes Heat

Generation

Heat Input Heat Output

A failure to balance heat input and heat output

Homeostasis the maintenance of relatively stable conditions in the

internal environment of the body despite variations in the external environment

Factors such as

ndash blood pressure ndash body temperature ndash respiration rate ndash blood glucose levels ndash pH ndash Ions ndash O2 and CO2 levels ndash Nutritional needs ndash H2O levels

bull are maintained within a range of normal values around a set point despite constantly changing external conditions

bull Homeostasis requires the body being able to

ndash detect external changes

ndash Implement internal changes to compensate

The Stimulus - Response Model

The Stimulus - Response Model

Heat

Cools

The Stimulus Response Model

How can the body control the response 1 Disrupt the signal transduction pathway

2 Removal of the original stimulus 3 Responding in a way that alters the original signal Feedback

2

1

Negative feedback mechanisms result in control

Negative Feedback result in control

Negative Feedback Mechanism

Positive feedback results in stimulating an effect

bull Works by adding to the stimulus and increasing the effect of it

Positive feedback

Positive feedback

Mechanisms enabling Homeostasis

Negative feedback model

Modes of Transmission Hormonal system bull Slow ( 30-178cmsec)

bull Involves chemical messengers

bull Act by binding to specific receptors on target cells after travelling through the blood stream

bull Can be more long term effect

Nervous system bull Fast ( 1-120msec)

bull Act by sending electrical impulses along neuron cells

bull Short term effect

The nervous system is a rapid response to stimuli It is a more direct communication pathway than hormones

Nerve Structure

The nervous system is made up of neuron cells that send an electrical impulse along from one neuron to the next

The nerve impulse is essentially an electro

chemical impulse resulting from the rapid movement

of ions across the membrane of the neurons

The Nerve impulse

Nerve impulse s are an electrical signal that travels along an axon There is an electrical difference between the inside of the axon and its surroundings When the nerve is activated there is a sudden change in the voltage across the wall of the axon caused by the movement of ions in and out of the neuron This triggers a wave of electrical activity that passes from the cell body along the length of the axon to the synapse

Processes Heat

Generation

Heat Input Heat Output

A failure to balance heat input and heat output

Homeostasis the maintenance of relatively stable conditions in the

internal environment of the body despite variations in the external environment

Factors such as

ndash blood pressure ndash body temperature ndash respiration rate ndash blood glucose levels ndash pH ndash Ions ndash O2 and CO2 levels ndash Nutritional needs ndash H2O levels

bull are maintained within a range of normal values around a set point despite constantly changing external conditions

bull Homeostasis requires the body being able to

ndash detect external changes

ndash Implement internal changes to compensate

The Stimulus - Response Model

The Stimulus - Response Model

Heat

Cools

The Stimulus Response Model

How can the body control the response 1 Disrupt the signal transduction pathway

2 Removal of the original stimulus 3 Responding in a way that alters the original signal Feedback

2

1

Negative feedback mechanisms result in control

Negative Feedback result in control

Negative Feedback Mechanism

Positive feedback results in stimulating an effect

bull Works by adding to the stimulus and increasing the effect of it

Positive feedback

Positive feedback

Mechanisms enabling Homeostasis

Negative feedback model

Modes of Transmission Hormonal system bull Slow ( 30-178cmsec)

bull Involves chemical messengers

bull Act by binding to specific receptors on target cells after travelling through the blood stream

bull Can be more long term effect

Nervous system bull Fast ( 1-120msec)

bull Act by sending electrical impulses along neuron cells

bull Short term effect

The nervous system is a rapid response to stimuli It is a more direct communication pathway than hormones

Nerve Structure

The nervous system is made up of neuron cells that send an electrical impulse along from one neuron to the next

The nerve impulse is essentially an electro

chemical impulse resulting from the rapid movement

of ions across the membrane of the neurons

The Nerve impulse

Nerve impulse s are an electrical signal that travels along an axon There is an electrical difference between the inside of the axon and its surroundings When the nerve is activated there is a sudden change in the voltage across the wall of the axon caused by the movement of ions in and out of the neuron This triggers a wave of electrical activity that passes from the cell body along the length of the axon to the synapse

A failure to balance heat input and heat output

Homeostasis the maintenance of relatively stable conditions in the

internal environment of the body despite variations in the external environment

Factors such as

ndash blood pressure ndash body temperature ndash respiration rate ndash blood glucose levels ndash pH ndash Ions ndash O2 and CO2 levels ndash Nutritional needs ndash H2O levels

bull are maintained within a range of normal values around a set point despite constantly changing external conditions

bull Homeostasis requires the body being able to

ndash detect external changes

ndash Implement internal changes to compensate

The Stimulus - Response Model

The Stimulus - Response Model

Heat

Cools

The Stimulus Response Model

How can the body control the response 1 Disrupt the signal transduction pathway

2 Removal of the original stimulus 3 Responding in a way that alters the original signal Feedback

2

1

Negative feedback mechanisms result in control

Negative Feedback result in control

Negative Feedback Mechanism

Positive feedback results in stimulating an effect

bull Works by adding to the stimulus and increasing the effect of it

Positive feedback

Positive feedback

Mechanisms enabling Homeostasis

Negative feedback model

Modes of Transmission Hormonal system bull Slow ( 30-178cmsec)

bull Involves chemical messengers

bull Act by binding to specific receptors on target cells after travelling through the blood stream

bull Can be more long term effect

Nervous system bull Fast ( 1-120msec)

bull Act by sending electrical impulses along neuron cells

bull Short term effect

The nervous system is a rapid response to stimuli It is a more direct communication pathway than hormones

Nerve Structure

The nervous system is made up of neuron cells that send an electrical impulse along from one neuron to the next

The nerve impulse is essentially an electro

chemical impulse resulting from the rapid movement

of ions across the membrane of the neurons

The Nerve impulse

Nerve impulse s are an electrical signal that travels along an axon There is an electrical difference between the inside of the axon and its surroundings When the nerve is activated there is a sudden change in the voltage across the wall of the axon caused by the movement of ions in and out of the neuron This triggers a wave of electrical activity that passes from the cell body along the length of the axon to the synapse

Homeostasis the maintenance of relatively stable conditions in the

internal environment of the body despite variations in the external environment

Factors such as

ndash blood pressure ndash body temperature ndash respiration rate ndash blood glucose levels ndash pH ndash Ions ndash O2 and CO2 levels ndash Nutritional needs ndash H2O levels

bull are maintained within a range of normal values around a set point despite constantly changing external conditions

bull Homeostasis requires the body being able to

ndash detect external changes

ndash Implement internal changes to compensate

The Stimulus - Response Model

The Stimulus - Response Model

Heat

Cools

The Stimulus Response Model

How can the body control the response 1 Disrupt the signal transduction pathway

2 Removal of the original stimulus 3 Responding in a way that alters the original signal Feedback

2

1

Negative feedback mechanisms result in control

Negative Feedback result in control

Negative Feedback Mechanism

Positive feedback results in stimulating an effect

bull Works by adding to the stimulus and increasing the effect of it

Positive feedback

Positive feedback

Mechanisms enabling Homeostasis

Negative feedback model

Modes of Transmission Hormonal system bull Slow ( 30-178cmsec)

bull Involves chemical messengers

bull Act by binding to specific receptors on target cells after travelling through the blood stream

bull Can be more long term effect

Nervous system bull Fast ( 1-120msec)

bull Act by sending electrical impulses along neuron cells

bull Short term effect

The nervous system is a rapid response to stimuli It is a more direct communication pathway than hormones

Nerve Structure

The nervous system is made up of neuron cells that send an electrical impulse along from one neuron to the next

The nerve impulse is essentially an electro

chemical impulse resulting from the rapid movement

of ions across the membrane of the neurons

The Nerve impulse

Nerve impulse s are an electrical signal that travels along an axon There is an electrical difference between the inside of the axon and its surroundings When the nerve is activated there is a sudden change in the voltage across the wall of the axon caused by the movement of ions in and out of the neuron This triggers a wave of electrical activity that passes from the cell body along the length of the axon to the synapse

bull Homeostasis requires the body being able to

ndash detect external changes

ndash Implement internal changes to compensate

The Stimulus - Response Model

The Stimulus - Response Model

Heat

Cools

The Stimulus Response Model

How can the body control the response 1 Disrupt the signal transduction pathway

2 Removal of the original stimulus 3 Responding in a way that alters the original signal Feedback

2

1

Negative feedback mechanisms result in control

Negative Feedback result in control

Negative Feedback Mechanism

Positive feedback results in stimulating an effect

bull Works by adding to the stimulus and increasing the effect of it

Positive feedback

Positive feedback

Mechanisms enabling Homeostasis

Negative feedback model

Modes of Transmission Hormonal system bull Slow ( 30-178cmsec)

bull Involves chemical messengers

bull Act by binding to specific receptors on target cells after travelling through the blood stream

bull Can be more long term effect

Nervous system bull Fast ( 1-120msec)

bull Act by sending electrical impulses along neuron cells

bull Short term effect

The nervous system is a rapid response to stimuli It is a more direct communication pathway than hormones

Nerve Structure

The nervous system is made up of neuron cells that send an electrical impulse along from one neuron to the next

The nerve impulse is essentially an electro

chemical impulse resulting from the rapid movement

of ions across the membrane of the neurons

The Nerve impulse

Nerve impulse s are an electrical signal that travels along an axon There is an electrical difference between the inside of the axon and its surroundings When the nerve is activated there is a sudden change in the voltage across the wall of the axon caused by the movement of ions in and out of the neuron This triggers a wave of electrical activity that passes from the cell body along the length of the axon to the synapse

The Stimulus - Response Model

The Stimulus - Response Model

Heat

Cools

The Stimulus Response Model

How can the body control the response 1 Disrupt the signal transduction pathway

2 Removal of the original stimulus 3 Responding in a way that alters the original signal Feedback

2

1

Negative feedback mechanisms result in control

Negative Feedback result in control

Negative Feedback Mechanism

Positive feedback results in stimulating an effect

bull Works by adding to the stimulus and increasing the effect of it

Positive feedback

Positive feedback

Mechanisms enabling Homeostasis

Negative feedback model

Modes of Transmission Hormonal system bull Slow ( 30-178cmsec)

bull Involves chemical messengers

bull Act by binding to specific receptors on target cells after travelling through the blood stream

bull Can be more long term effect

Nervous system bull Fast ( 1-120msec)

bull Act by sending electrical impulses along neuron cells

bull Short term effect

The nervous system is a rapid response to stimuli It is a more direct communication pathway than hormones

Nerve Structure

The nervous system is made up of neuron cells that send an electrical impulse along from one neuron to the next

The nerve impulse is essentially an electro

chemical impulse resulting from the rapid movement

of ions across the membrane of the neurons

The Nerve impulse

Nerve impulse s are an electrical signal that travels along an axon There is an electrical difference between the inside of the axon and its surroundings When the nerve is activated there is a sudden change in the voltage across the wall of the axon caused by the movement of ions in and out of the neuron This triggers a wave of electrical activity that passes from the cell body along the length of the axon to the synapse

The Stimulus - Response Model

Heat

Cools

The Stimulus Response Model

How can the body control the response 1 Disrupt the signal transduction pathway

2 Removal of the original stimulus 3 Responding in a way that alters the original signal Feedback

2

1

Negative feedback mechanisms result in control

Negative Feedback result in control

Negative Feedback Mechanism

Positive feedback results in stimulating an effect

bull Works by adding to the stimulus and increasing the effect of it

Positive feedback

Positive feedback

Mechanisms enabling Homeostasis

Negative feedback model

Modes of Transmission Hormonal system bull Slow ( 30-178cmsec)

bull Involves chemical messengers

bull Act by binding to specific receptors on target cells after travelling through the blood stream

bull Can be more long term effect

Nervous system bull Fast ( 1-120msec)

bull Act by sending electrical impulses along neuron cells

bull Short term effect

The nervous system is a rapid response to stimuli It is a more direct communication pathway than hormones

Nerve Structure

The nervous system is made up of neuron cells that send an electrical impulse along from one neuron to the next

The nerve impulse is essentially an electro

chemical impulse resulting from the rapid movement

of ions across the membrane of the neurons

The Nerve impulse

Nerve impulse s are an electrical signal that travels along an axon There is an electrical difference between the inside of the axon and its surroundings When the nerve is activated there is a sudden change in the voltage across the wall of the axon caused by the movement of ions in and out of the neuron This triggers a wave of electrical activity that passes from the cell body along the length of the axon to the synapse

The Stimulus Response Model

How can the body control the response 1 Disrupt the signal transduction pathway

2 Removal of the original stimulus 3 Responding in a way that alters the original signal Feedback

2

1

Negative feedback mechanisms result in control

Negative Feedback result in control

Negative Feedback Mechanism

Positive feedback results in stimulating an effect

bull Works by adding to the stimulus and increasing the effect of it

Positive feedback

Positive feedback

Mechanisms enabling Homeostasis

Negative feedback model

Modes of Transmission Hormonal system bull Slow ( 30-178cmsec)

bull Involves chemical messengers

bull Act by binding to specific receptors on target cells after travelling through the blood stream

bull Can be more long term effect

Nervous system bull Fast ( 1-120msec)

bull Act by sending electrical impulses along neuron cells

bull Short term effect

The nervous system is a rapid response to stimuli It is a more direct communication pathway than hormones

Nerve Structure

The nervous system is made up of neuron cells that send an electrical impulse along from one neuron to the next

The nerve impulse is essentially an electro

chemical impulse resulting from the rapid movement

of ions across the membrane of the neurons

The Nerve impulse

Nerve impulse s are an electrical signal that travels along an axon There is an electrical difference between the inside of the axon and its surroundings When the nerve is activated there is a sudden change in the voltage across the wall of the axon caused by the movement of ions in and out of the neuron This triggers a wave of electrical activity that passes from the cell body along the length of the axon to the synapse

Negative feedback mechanisms result in control

Negative Feedback result in control

Negative Feedback Mechanism

Positive feedback results in stimulating an effect

bull Works by adding to the stimulus and increasing the effect of it

Positive feedback

Positive feedback

Mechanisms enabling Homeostasis

Negative feedback model

Modes of Transmission Hormonal system bull Slow ( 30-178cmsec)

bull Involves chemical messengers

bull Act by binding to specific receptors on target cells after travelling through the blood stream

bull Can be more long term effect

Nervous system bull Fast ( 1-120msec)

bull Act by sending electrical impulses along neuron cells

bull Short term effect

The nervous system is a rapid response to stimuli It is a more direct communication pathway than hormones

Nerve Structure

The nervous system is made up of neuron cells that send an electrical impulse along from one neuron to the next

The nerve impulse is essentially an electro

chemical impulse resulting from the rapid movement

of ions across the membrane of the neurons

The Nerve impulse

Nerve impulse s are an electrical signal that travels along an axon There is an electrical difference between the inside of the axon and its surroundings When the nerve is activated there is a sudden change in the voltage across the wall of the axon caused by the movement of ions in and out of the neuron This triggers a wave of electrical activity that passes from the cell body along the length of the axon to the synapse

Negative Feedback result in control

Negative Feedback Mechanism

Positive feedback results in stimulating an effect

bull Works by adding to the stimulus and increasing the effect of it

Positive feedback

Positive feedback

Mechanisms enabling Homeostasis

Negative feedback model

Modes of Transmission Hormonal system bull Slow ( 30-178cmsec)

bull Involves chemical messengers

bull Act by binding to specific receptors on target cells after travelling through the blood stream

bull Can be more long term effect

Nervous system bull Fast ( 1-120msec)

bull Act by sending electrical impulses along neuron cells

bull Short term effect

The nervous system is a rapid response to stimuli It is a more direct communication pathway than hormones

Nerve Structure

The nervous system is made up of neuron cells that send an electrical impulse along from one neuron to the next

The nerve impulse is essentially an electro

chemical impulse resulting from the rapid movement

of ions across the membrane of the neurons

The Nerve impulse

Nerve impulse s are an electrical signal that travels along an axon There is an electrical difference between the inside of the axon and its surroundings When the nerve is activated there is a sudden change in the voltage across the wall of the axon caused by the movement of ions in and out of the neuron This triggers a wave of electrical activity that passes from the cell body along the length of the axon to the synapse

Negative Feedback Mechanism

Positive feedback results in stimulating an effect

bull Works by adding to the stimulus and increasing the effect of it

Positive feedback

Positive feedback

Mechanisms enabling Homeostasis

Negative feedback model

Modes of Transmission Hormonal system bull Slow ( 30-178cmsec)

bull Involves chemical messengers

bull Act by binding to specific receptors on target cells after travelling through the blood stream

bull Can be more long term effect

Nervous system bull Fast ( 1-120msec)

bull Act by sending electrical impulses along neuron cells

bull Short term effect

The nervous system is a rapid response to stimuli It is a more direct communication pathway than hormones

Nerve Structure

The nervous system is made up of neuron cells that send an electrical impulse along from one neuron to the next

The nerve impulse is essentially an electro

chemical impulse resulting from the rapid movement

of ions across the membrane of the neurons

The Nerve impulse

Nerve impulse s are an electrical signal that travels along an axon There is an electrical difference between the inside of the axon and its surroundings When the nerve is activated there is a sudden change in the voltage across the wall of the axon caused by the movement of ions in and out of the neuron This triggers a wave of electrical activity that passes from the cell body along the length of the axon to the synapse

Positive feedback results in stimulating an effect

bull Works by adding to the stimulus and increasing the effect of it

Positive feedback

Positive feedback

Mechanisms enabling Homeostasis

Negative feedback model

Modes of Transmission Hormonal system bull Slow ( 30-178cmsec)

bull Involves chemical messengers

bull Act by binding to specific receptors on target cells after travelling through the blood stream

bull Can be more long term effect

Nervous system bull Fast ( 1-120msec)

bull Act by sending electrical impulses along neuron cells

bull Short term effect

The nervous system is a rapid response to stimuli It is a more direct communication pathway than hormones

Nerve Structure

The nervous system is made up of neuron cells that send an electrical impulse along from one neuron to the next

The nerve impulse is essentially an electro

chemical impulse resulting from the rapid movement

of ions across the membrane of the neurons

The Nerve impulse

Nerve impulse s are an electrical signal that travels along an axon There is an electrical difference between the inside of the axon and its surroundings When the nerve is activated there is a sudden change in the voltage across the wall of the axon caused by the movement of ions in and out of the neuron This triggers a wave of electrical activity that passes from the cell body along the length of the axon to the synapse

Positive feedback

Positive feedback

Mechanisms enabling Homeostasis

Negative feedback model

Modes of Transmission Hormonal system bull Slow ( 30-178cmsec)

bull Involves chemical messengers

bull Act by binding to specific receptors on target cells after travelling through the blood stream

bull Can be more long term effect

Nervous system bull Fast ( 1-120msec)

bull Act by sending electrical impulses along neuron cells

bull Short term effect

The nervous system is a rapid response to stimuli It is a more direct communication pathway than hormones

Nerve Structure

The nervous system is made up of neuron cells that send an electrical impulse along from one neuron to the next

The nerve impulse is essentially an electro

chemical impulse resulting from the rapid movement

of ions across the membrane of the neurons

The Nerve impulse

Nerve impulse s are an electrical signal that travels along an axon There is an electrical difference between the inside of the axon and its surroundings When the nerve is activated there is a sudden change in the voltage across the wall of the axon caused by the movement of ions in and out of the neuron This triggers a wave of electrical activity that passes from the cell body along the length of the axon to the synapse

Positive feedback

Mechanisms enabling Homeostasis

Negative feedback model

Modes of Transmission Hormonal system bull Slow ( 30-178cmsec)

bull Involves chemical messengers

bull Act by binding to specific receptors on target cells after travelling through the blood stream

bull Can be more long term effect

Nervous system bull Fast ( 1-120msec)

bull Act by sending electrical impulses along neuron cells

bull Short term effect

The nervous system is a rapid response to stimuli It is a more direct communication pathway than hormones

Nerve Structure

The nervous system is made up of neuron cells that send an electrical impulse along from one neuron to the next

The nerve impulse is essentially an electro

chemical impulse resulting from the rapid movement

of ions across the membrane of the neurons

The Nerve impulse

Nerve impulse s are an electrical signal that travels along an axon There is an electrical difference between the inside of the axon and its surroundings When the nerve is activated there is a sudden change in the voltage across the wall of the axon caused by the movement of ions in and out of the neuron This triggers a wave of electrical activity that passes from the cell body along the length of the axon to the synapse

Mechanisms enabling Homeostasis

Negative feedback model

Modes of Transmission Hormonal system bull Slow ( 30-178cmsec)

bull Involves chemical messengers

bull Act by binding to specific receptors on target cells after travelling through the blood stream

bull Can be more long term effect

Nervous system bull Fast ( 1-120msec)

bull Act by sending electrical impulses along neuron cells

bull Short term effect

The nervous system is a rapid response to stimuli It is a more direct communication pathway than hormones

Nerve Structure

The nervous system is made up of neuron cells that send an electrical impulse along from one neuron to the next

The nerve impulse is essentially an electro

chemical impulse resulting from the rapid movement

of ions across the membrane of the neurons

The Nerve impulse

Nerve impulse s are an electrical signal that travels along an axon There is an electrical difference between the inside of the axon and its surroundings When the nerve is activated there is a sudden change in the voltage across the wall of the axon caused by the movement of ions in and out of the neuron This triggers a wave of electrical activity that passes from the cell body along the length of the axon to the synapse

Modes of Transmission Hormonal system bull Slow ( 30-178cmsec)

bull Involves chemical messengers

bull Act by binding to specific receptors on target cells after travelling through the blood stream

bull Can be more long term effect

Nervous system bull Fast ( 1-120msec)

bull Act by sending electrical impulses along neuron cells

bull Short term effect

The nervous system is a rapid response to stimuli It is a more direct communication pathway than hormones

Nerve Structure

The nervous system is made up of neuron cells that send an electrical impulse along from one neuron to the next

The nerve impulse is essentially an electro

chemical impulse resulting from the rapid movement

of ions across the membrane of the neurons

The Nerve impulse

Nerve impulse s are an electrical signal that travels along an axon There is an electrical difference between the inside of the axon and its surroundings When the nerve is activated there is a sudden change in the voltage across the wall of the axon caused by the movement of ions in and out of the neuron This triggers a wave of electrical activity that passes from the cell body along the length of the axon to the synapse

The nervous system is a rapid response to stimuli It is a more direct communication pathway than hormones

Nerve Structure

The nervous system is made up of neuron cells that send an electrical impulse along from one neuron to the next

The nerve impulse is essentially an electro

chemical impulse resulting from the rapid movement

of ions across the membrane of the neurons

The Nerve impulse

Nerve impulse s are an electrical signal that travels along an axon There is an electrical difference between the inside of the axon and its surroundings When the nerve is activated there is a sudden change in the voltage across the wall of the axon caused by the movement of ions in and out of the neuron This triggers a wave of electrical activity that passes from the cell body along the length of the axon to the synapse

Nerve Structure

The nervous system is made up of neuron cells that send an electrical impulse along from one neuron to the next

The nerve impulse is essentially an electro

chemical impulse resulting from the rapid movement

of ions across the membrane of the neurons

The Nerve impulse

Nerve impulse s are an electrical signal that travels along an axon There is an electrical difference between the inside of the axon and its surroundings When the nerve is activated there is a sudden change in the voltage across the wall of the axon caused by the movement of ions in and out of the neuron This triggers a wave of electrical activity that passes from the cell body along the length of the axon to the synapse

The nervous system is made up of neuron cells that send an electrical impulse along from one neuron to the next

The nerve impulse is essentially an electro

chemical impulse resulting from the rapid movement

of ions across the membrane of the neurons

The Nerve impulse

Nerve impulse s are an electrical signal that travels along an axon There is an electrical difference between the inside of the axon and its surroundings When the nerve is activated there is a sudden change in the voltage across the wall of the axon caused by the movement of ions in and out of the neuron This triggers a wave of electrical activity that passes from the cell body along the length of the axon to the synapse

The nerve impulse is essentially an electro

chemical impulse resulting from the rapid movement

of ions across the membrane of the neurons

The Nerve impulse

Nerve impulse s are an electrical signal that travels along an axon There is an electrical difference between the inside of the axon and its surroundings When the nerve is activated there is a sudden change in the voltage across the wall of the axon caused by the movement of ions in and out of the neuron This triggers a wave of electrical activity that passes from the cell body along the length of the axon to the synapse

The Nerve impulse

Nerve impulse s are an electrical signal that travels along an axon There is an electrical difference between the inside of the axon and its surroundings When the nerve is activated there is a sudden change in the voltage across the wall of the axon caused by the movement of ions in and out of the neuron This triggers a wave of electrical activity that passes from the cell body along the length of the axon to the synapse

Action Potentials

The synapse the gap between the neurons

The Synapse

There are hundreds of different types of neurotransmitters each of which control something different This makes the nervous system controllable meaning some neurotransmitter initiate a response while others block a response

Neurotransmitters

Basic types of neurons

receptor effector

Receptors in the Skin

Types of sensory receptors

CNS

bull Many responses are a reflex not under conscious control

Somatic v Autonomic Nervous System

The Autonomic Nervous System

Hormones Hormones are signalling molecules or chemical messengers that control many functions in the bodies of organisms eg temperature blood glucose levels calcium uptake and many many more are controlled by hormones

bull Cells that produce hormones and are clustered into organs

Hypothalamus

bull One function of the hypothalamus is to link the nervous system to the endocrine system via the pituitary gland

bull The Hypothalamus is the control center for many autonomic functions of the peripheral nervous system

bull Connections with structures of the endocrine and nervous systems enable the hypothalamus to play a vital role in maintaining homeostasis

receptor effector

Receptors in the Skin

Types of sensory receptors

CNS

bull Many responses are a reflex not under conscious control

Somatic v Autonomic Nervous System

The Autonomic Nervous System

Hormones Hormones are signalling molecules or chemical messengers that control many functions in the bodies of organisms eg temperature blood glucose levels calcium uptake and many many more are controlled by hormones

bull Cells that produce hormones and are clustered into organs

Hypothalamus

bull One function of the hypothalamus is to link the nervous system to the endocrine system via the pituitary gland

bull The Hypothalamus is the control center for many autonomic functions of the peripheral nervous system

bull Connections with structures of the endocrine and nervous systems enable the hypothalamus to play a vital role in maintaining homeostasis

Receptors in the Skin

Types of sensory receptors

CNS

bull Many responses are a reflex not under conscious control

Somatic v Autonomic Nervous System

The Autonomic Nervous System

Hormones Hormones are signalling molecules or chemical messengers that control many functions in the bodies of organisms eg temperature blood glucose levels calcium uptake and many many more are controlled by hormones

bull Cells that produce hormones and are clustered into organs

Hypothalamus

bull One function of the hypothalamus is to link the nervous system to the endocrine system via the pituitary gland

bull The Hypothalamus is the control center for many autonomic functions of the peripheral nervous system

bull Connections with structures of the endocrine and nervous systems enable the hypothalamus to play a vital role in maintaining homeostasis

Types of sensory receptors

CNS

bull Many responses are a reflex not under conscious control

Somatic v Autonomic Nervous System

The Autonomic Nervous System

Hormones Hormones are signalling molecules or chemical messengers that control many functions in the bodies of organisms eg temperature blood glucose levels calcium uptake and many many more are controlled by hormones

bull Cells that produce hormones and are clustered into organs

Hypothalamus

bull One function of the hypothalamus is to link the nervous system to the endocrine system via the pituitary gland

bull The Hypothalamus is the control center for many autonomic functions of the peripheral nervous system

bull Connections with structures of the endocrine and nervous systems enable the hypothalamus to play a vital role in maintaining homeostasis

CNS

bull Many responses are a reflex not under conscious control

Somatic v Autonomic Nervous System

The Autonomic Nervous System

Hormones Hormones are signalling molecules or chemical messengers that control many functions in the bodies of organisms eg temperature blood glucose levels calcium uptake and many many more are controlled by hormones

bull Cells that produce hormones and are clustered into organs

Hypothalamus

bull One function of the hypothalamus is to link the nervous system to the endocrine system via the pituitary gland

bull The Hypothalamus is the control center for many autonomic functions of the peripheral nervous system

bull Connections with structures of the endocrine and nervous systems enable the hypothalamus to play a vital role in maintaining homeostasis

bull Many responses are a reflex not under conscious control

Somatic v Autonomic Nervous System

The Autonomic Nervous System

Hormones Hormones are signalling molecules or chemical messengers that control many functions in the bodies of organisms eg temperature blood glucose levels calcium uptake and many many more are controlled by hormones

bull Cells that produce hormones and are clustered into organs

Hypothalamus

bull One function of the hypothalamus is to link the nervous system to the endocrine system via the pituitary gland

bull The Hypothalamus is the control center for many autonomic functions of the peripheral nervous system

bull Connections with structures of the endocrine and nervous systems enable the hypothalamus to play a vital role in maintaining homeostasis

Somatic v Autonomic Nervous System

The Autonomic Nervous System

Hormones Hormones are signalling molecules or chemical messengers that control many functions in the bodies of organisms eg temperature blood glucose levels calcium uptake and many many more are controlled by hormones

bull Cells that produce hormones and are clustered into organs

Hypothalamus

bull One function of the hypothalamus is to link the nervous system to the endocrine system via the pituitary gland

bull The Hypothalamus is the control center for many autonomic functions of the peripheral nervous system

bull Connections with structures of the endocrine and nervous systems enable the hypothalamus to play a vital role in maintaining homeostasis

The Autonomic Nervous System

Hormones Hormones are signalling molecules or chemical messengers that control many functions in the bodies of organisms eg temperature blood glucose levels calcium uptake and many many more are controlled by hormones

bull Cells that produce hormones and are clustered into organs

Hypothalamus

bull One function of the hypothalamus is to link the nervous system to the endocrine system via the pituitary gland

bull The Hypothalamus is the control center for many autonomic functions of the peripheral nervous system

bull Connections with structures of the endocrine and nervous systems enable the hypothalamus to play a vital role in maintaining homeostasis

Hormones Hormones are signalling molecules or chemical messengers that control many functions in the bodies of organisms eg temperature blood glucose levels calcium uptake and many many more are controlled by hormones

bull Cells that produce hormones and are clustered into organs

Hypothalamus

bull One function of the hypothalamus is to link the nervous system to the endocrine system via the pituitary gland

bull The Hypothalamus is the control center for many autonomic functions of the peripheral nervous system

bull Connections with structures of the endocrine and nervous systems enable the hypothalamus to play a vital role in maintaining homeostasis

bull Cells that produce hormones and are clustered into organs

Hypothalamus

bull One function of the hypothalamus is to link the nervous system to the endocrine system via the pituitary gland

bull The Hypothalamus is the control center for many autonomic functions of the peripheral nervous system

bull Connections with structures of the endocrine and nervous systems enable the hypothalamus to play a vital role in maintaining homeostasis

Hypothalamus

bull One function of the hypothalamus is to link the nervous system to the endocrine system via the pituitary gland

bull The Hypothalamus is the control center for many autonomic functions of the peripheral nervous system

bull Connections with structures of the endocrine and nervous systems enable the hypothalamus to play a vital role in maintaining homeostasis

The pituitary gland secretes hormones regulating homeostasis including tropic hormones that stimulate other endocrine glands It is considered to be the master gland

Cushings disease-Pituitary Gland

Hormones at work

The Fight or Flight Response

Receptors Visual Auditory

When the homeostatic control of Blood sugar is disrupted Diabetes

bull Type 1 Diabetes

bull Type 2 Diabetes

When the homeostatic control of Blood sugar is disrupted Diabetes

bull Type 1 Diabetes

bull Type 2 Diabetes

Thermoregulation animation

countercurrent heat exchange

A kind of dormancy shown by insects where they pause a part of their lifecycle (Flies in winter)

When food is scare and the temperature is low Some animals canrsquot maintain a stable internal temperature So instead they hibernate (Below Dormice)

Hibernate Diapause

Ways that water can be lost

bull Panting in dogs dingos amp wolves

bull Sweating

bull Urine

bull Faeces

Ways to save or increase water supply

bull Thirst response- experienced as the concentration of water in the blood is lowered

bull Waterproof barriers like hair feathers scales and skin protect against evaporative water loss

bull Reabsorption of water from the large intestine

bull Increase in concentration of urine by increasing reabsorption of water in

Kidneys bull Storage of water

ndash (Desert frogs store water in a cocoon ndash Camelrsquos store fat in their hump and

metabolise the fat to gain water

Saltwater bull Marine saltwater animals tend

to have body fluids that are HYPOTONIC to their surroundings So they lose water via osmosis to their surroundings

bull To gain more water they drink salt water and must spend a lot of energy removing salt from their body

Freshwater

bull Freshwater animals have lots of water in their surroundings but have body fluids that are HYPERTONIC to their surroundings So they can gain too much water from their surroundings causing their cells to burst

External Hi H2O LO Salts External LO H2O Hi Salts

Internal Hi H2O LO Salts Internal LO H2O Hi Salts

Ways that water can be lost

bull Panting in dogs dingos amp wolves

bull Sweating

bull Urine

bull Faeces

Ways to save or increase water supply

bull Thirst response- experienced as the concentration of water in the blood is lowered

bull Waterproof barriers like hair feathers scales and skin protect against evaporative water loss

bull Reabsorption of water from the large intestine

bull Increase in concentration of urine by increasing reabsorption of water in

Kidneys bull Storage of water

ndash (Desert frogs store water in a cocoon ndash Camelrsquos store fat in their hump and

metabolise the fat to gain water

Saltwater bull Marine saltwater animals tend

to have body fluids that are HYPOTONIC to their surroundings So they lose water via osmosis to their surroundings

bull To gain more water they drink salt water and must spend a lot of energy removing salt from their body

Freshwater

bull Freshwater animals have lots of water in their surroundings but have body fluids that are HYPERTONIC to their surroundings So they can gain too much water from their surroundings causing their cells to burst

External Hi H2O LO Salts External LO H2O Hi Salts

Internal Hi H2O LO Salts Internal LO H2O Hi Salts

Ways to save or increase water supply

bull Thirst response- experienced as the concentration of water in the blood is lowered

bull Waterproof barriers like hair feathers scales and skin protect against evaporative water loss

bull Reabsorption of water from the large intestine

bull Increase in concentration of urine by increasing reabsorption of water in

Kidneys bull Storage of water

ndash (Desert frogs store water in a cocoon ndash Camelrsquos store fat in their hump and

metabolise the fat to gain water

Saltwater bull Marine saltwater animals tend

to have body fluids that are HYPOTONIC to their surroundings So they lose water via osmosis to their surroundings

bull To gain more water they drink salt water and must spend a lot of energy removing salt from their body

Freshwater

bull Freshwater animals have lots of water in their surroundings but have body fluids that are HYPERTONIC to their surroundings So they can gain too much water from their surroundings causing their cells to burst

External Hi H2O LO Salts External LO H2O Hi Salts

Internal Hi H2O LO Salts Internal LO H2O Hi Salts

Saltwater bull Marine saltwater animals tend

to have body fluids that are HYPOTONIC to their surroundings So they lose water via osmosis to their surroundings

bull To gain more water they drink salt water and must spend a lot of energy removing salt from their body

Freshwater

bull Freshwater animals have lots of water in their surroundings but have body fluids that are HYPERTONIC to their surroundings So they can gain too much water from their surroundings causing their cells to burst

External Hi H2O LO Salts External LO H2O Hi Salts

Internal Hi H2O LO Salts Internal LO H2O Hi Salts

External Hi H2O LO Salts External LO H2O Hi Salts

Internal Hi H2O LO Salts Internal LO H2O Hi Salts